EP-PS 0 060 054 discloses a multi-pole vacuum switch arrangement with a mobile rack. A one-piece insulating supporting part is secured backwards onto this rack, said insulating supporting part having three recesses arranged next to one another and open to the front, in which in each case one vacuum switch tube is secured. A housing is also secured on the rack, in which housing a drive, for example a spring-force drive, is arranged which is connected via linkages to the movable switch contacts of the vacuum switch tubes. Towards the bottom there are projecting extensions formed onto the insulating supporting part which form bearing points for double-armed levers of the linkages. Although this insulating supporting part assumes a plurality of functions, the construction of the entire switch arrangement is still costly.
U.S. Pat. No. 4,587,390 discloses a further switch arrangement. This has a housing containing a spring-force drive, on which housing three tubular insulating frames are arranged in an upright manner. In each insulating supporting frame, a vacuum switch tube is secured, the contacts of which are connected in each case to one connecting conductor which penetrates the respective insulating supporting frame in a radial direction. In the housing of the spring-force drive, two parallel shields laterally spaced from one another are provided, on which the drive parts of the spring-force drive are mounted. Each movable contact of the vacuum switch tubes is operatively connected via, in each case, one linkage to the drive member, which is common to all the poles, of the spring-force drive. This switch arrangement has many individual parts and its construction and installation are costly.
In the Swiss Patent Application No. 2283/88-0, which is not a prior publication, corresponding to U.S. Pat. application Ser. No. 07/361,257 now U.S. Pat. No. 5,015,809 a multi-pole vacuum switch arrangement is described which has a single insulating supporting part which receives the vacuum switch tubes of all the poles and on which a bearing part or a plurality of bearing parts to bear parts of the spring-force drive is provided. This insulating supporting part is secured on a plate-shaped, mobile, metal rack.